This invention relates to a combustion apparatus including a burner head unit for burning a mixture of air and a liquid fuel in a gaseous state or in an atomized particle state or a mixture of air and a gaseous fuel, and a blower unit for supplying secondary air to a flame formed by the combustion of the fuel-air mixture in the burner head unit. The invention is directed particularly to a combustion apparatus of high combustion efficiency having a wide range of combustion.
In combustion apparatus, one of the important problems is how to increase combustion efficiency and widen the range of combustion. This problem can be solved by providing an improved flame of combustion and by obtaining better mixing of the fuel with air.
To this end, it has hitherto been common practice to supply a mixture of fuel with primary air to the burner head for burning the mixture and forming a flame of combustion, and to blow secondary air into the central portion of the flame from its periphery. In some applications, the secondary air is supplied in a vortical state. However, combustion apparatuses of the prior art have had disadvantages in that the flame does not remain stable and the combustion of the fuel-air mixture produces noise. Moreover, a flame has a self-tightening property, and this makes it difficult to introduce the secondary air to the central portion of a flame. Thus combustion apparatuses of the prior art have been unsuccessful in increasing combustion efficiency and widening the range of combustion above a certain level.